Contact construction for switches or the like



July 4, 1967 w. N. scHiNK 3,329,790

CONTACT CONSTRUCTION FOR SWITCHES OR THE LIKE Filed July 2, 1964 2Sheets-Sheet l [AWE/V7012 Wz' [110m Al. Sc/zirzk w. N. SCHINK 3,329,790

CONTACT CONSTRUCTION FOR SWITCHES OR THE LIKE July 4, 1967 Filed July 2,1964 2 Sheets-Sheet 2 INVEN r02 United States Patent 3,329,790 CONTACTCONSTRUCTION FOR SWITCHES OR THE LIKE William N. Scllink, Crystal Lake,Ill., assignor to Indak Manufacturing Corp., Northbrook, Ill., acorporation of Illinois Filed July 2, 1964, Ser. No. 379,894 3 Claims.(Cl. 200-166) This invention relates generally to electrical switches orthe like and pertains particularly to a contact construction and amethod of making the same.

One object of the present invention is to provide a new and improvedcontact construction in which a plurality of contact segments aremounted on an insulating board which has semi-perforated segmentalmembers projecting therefrom between said segments to locate saidsegments on said board while also providing slide surfaces for smoothcontact movement between said segments.

A further object is to provide such a new and improved contactconstruction in which each contact segment is secured to the insulatingboard by a single rivet or other similar fastener, and in which thesemi-perforated members prevent rotation of the contact segments aboutthe rivets.

Another object is to provide a new and improved method involving theinitial step of forming a plurality of contact segments as a singlepiece or unit, stamped from sheet metal, and with an interconnectingouter spider. The unit is then mounted on an insulating board havingsemiperforated projections which extend between the contact segments. Asingle rivet or other fastener is employed to secure each contactsegment to the board. The outer spider is then trimmed away or otherwiseremoved. The semiperforated projections prevent rotation of the contactsegments about the rivets.

Still another object is to provide a new and improved terminalconstruction in which a terminal member is secured to a terminal boardby a rivet or the like, and in which the terminal member is formed witha locating prong which projects into a recess extending only part waythrough the terminal board adjacent the rivet hole, the recess beingsqueezed into the insulating board.

A further object is to provide a new and improved contact constructionwhich is efficient and extremely durable yet is easy to manufacture andlow in cost.

Further objects and advantages of the present invention will appear fromthe following description, taken with the accompanying drawings, inwhich:

FIG. 1 is a side elevational view of an electrical switch to bedescribed as an illustrative embodiment of the present invention.

FIG. 2 is a rear elevational View of the switch.

FIG. 3 is a front elevational view.

FIG. 4 is an enlarged longitudinal section through the switch, takengenerally along the line 4-4 in FIG. 5.

FIG. 5 is a cross-sectional view taken generally along the line 55 inFIG. 4.

FIG. 6 is a front view of the insulating board employed to support thecontact segments and terminals in the switch of FIGS. 1-5.

FIG. 7 is a front elevational view of a one-piece metal stamping whichis mounted on the insulating board to provide all of the contactsegments, after which the outer spider portion of the stamping istrimmed away.

FIG. 8 is a fragmentary enlarged somewhat diagrammatic sectional viewtaken generally along the line 8-8 in FIG. 6.

FIG. 9 is an elevational view of a different construction, forminganother illustrative embodiment of the present invention.

FIG. 10 is a fragmentary enlarged section taken generally along the line1tl10 in FIG. 9.

3,329,790 Patented July 4, 1967 FIG. 11 is a fragmentary section takengenerally along the arcuate line 11--11 in FIG. 9.

The contact and terminal construction of the present invention will bedescribed as embodied in a rotary electrical switch 20, shown generallyin FIGS. 1-3. The switch is of the general type disclosed and claimed inthe Soreng patent, No. 2,868,906, patented Jan. 13, 1959, and assignedto the same assignee as the present application. It will be seen thatthe switch 20 comprises a rotary operating shaft 22 to which a knob 24is secured. The switch may also be arranged for key operation, ifdesired. The shaft 22 is rotatably mounted in a bearing sleeve orbushing 26 which extends forwardly from the front wall 28 of a generallycylindrical cup-shaped casing or housing 30. The switch 20 is adaptedfor mounting on a panel 32 having an opening 34 therein for receivingthe bushing 26. Screw threads 36 are formed on the bushing 26 to receivea nut 38 for securing the switch to the panel 32. Within the casing 30,the switch has an insulating rotor 40 which may be made of variousplastics or other suitable insulating material. The rotor 40 has a hub42 which is suitably connected to the shaft 22 and is rotatabletherewith.

In this case, the rotor 40 carries two diametrically 0pposite contactors44, but the contactor arrangement may be varied to accomplish variousswitching functions. Each of the illustrated contactors 44 comprises ametal plate 46 which faces rearwardly and is in a radial planeperpendicular to the axis of the rotor 40. An inner contact point 47 andtwo outer contact points 48 and 49 project rearwardly from the plate 46.The contact points 47-49 are generally hemispherical in shape. It willbe seen that the contact points 47-49 are arranged in a triangle, andthat the plate 46 is generally triangular in shape.

Each contactor 44 has a pair of prongs 50 and 51 which project intoguide slots or openings 52 and 53 formed in the rear side of the rotor44. Thus, the contactors 44 are guided for movement from front to rear.A spring 54 is compressed between the rotor 40 and each contactor 44 andis effective to bias the contactor rearwardly, away from the rotor. Eachspring 54 is received in a socket or slot 56 formed in the rear of therotor 40.

In the illustrated switch, the contactors 44 are engageable with aninner or central contact segment 60 and five outer contact segments61-65 which are mounted to the rear of the rotor 40 and in a radialplane perpendicular to the axis thereof. The central segment 60 and theouter segment 61 are connected together and may be formed in one piece,but the other segments 62-65 .are insulated from each other and from thesegments 60 and 61. The outer segments 61-65 are arranged in a circlearound the central segment 60. It will be seen that the inner contactpoints 47 on the contactors 44 are engageable with the central segment60, while the outer contact points 48 and 49 are engageable with theouter contact segments 61-65. The contactors 44 are adapted to act asbridges to complete various electrical circuits between the centralsegment 6i and the outer segments 61-65.

The segments 60-65 are in the form of metal plates mounted on aninsulating terminal board or plate 68 wh-ich is circular in shape andcloses the rear side of the casing 30. In this case, the insulatingboard'68 is secured to the casing 30 by a flange portion 70 thereonwhich is turned inwardly behind the insulating board.

The insulating board 68 may be made of a suitable insulating material,such as a phenolic plastic, for example, preferably having a surfacecoating 72 made of a heatresistant material such as melamine plastic.

The illustrated contact segments 61-65 are secured to the insulatingboard 68 by suitable fasteners which may take the form of rivets 81-85.Holes 86-90 are formed in the insulating board 68 to receive the rivets81-85. The

"8 7: central contact segment 60 is part of the segment 61 and issecured to the insulating board 68 by the rivet 81.

The rear ends of the rivets 81-85 project behind the insulating board 68and are employed to secure terminal lugs 91-95 to the rear side of theinsulating board. In this case, a resistor 96 is connected between theterminal lugs 93 and 95, which are somewhat longer than the others. Theresistor 96 is in the form of a coil of resistance Wire. The terminal 91may be connected to the battery or other source of power, while theother terminals 92-95 may be connected to lighting circuits or the likewhich are adapted to be controlled by the switch. The illustrated switchis intended particularly for controlling the lights on an automotivevehicle, but may be used for various other applications.

Each of the illustrated terminal lugs 91-95 is bent into an L-shape toform a base portion 98 and a rearwardly projecting leg 100. In eachcase, the base portion 98 is clamped against the rear of the terminalboard 68 by the corresponding rivet. Thus, a rivet hole 101 is formed ineach base portion 98. Means may be provided to connect leads to therearwardly projecting legs 100. Thus, some or all of the legs 100 may befitted with terminal screws 102.

To prevent the terminal lugs 91-95 from turning about the rivets 81-85,the base portion 98 of each terminal lug is formed with a prong 104which projects forwardly adjacent the rivet hole 101. Some of the rivetholes in the insulating board 68 are formed with key ways or slots 106to receive the prongs 104. Thus, such key ways 106 connect with theouter side portions of the rivet holes 86, 88 and 90, as shown in FIG.6. In the case of each of the remaining rivet holes 87 and 89, a recess108 is formed in the rear side of the insulating board 68 adjacent theouter side portion of the rivet hole. The recess 108 extends only partway through the insulating board 68. Each recess 108 may be formed by adie operation in which the recess is squeezed into the insulating board68 by a die which applies high pressure to the area in which the recessis to be formed.

In this case, the central contact segment 60 is formed with an axialeyelet or bushing 110 which provides a rear bearing for the rotor 40.The eyelet 110 is cylindrical in shape and is formed integrally with thecentral contact segment 60. It will be seen that the eyelet 110 projectsforwardly into a socket or bore 112 formed in the rear side of the rotor40. The front of the rotor 40 is supported by the shaft 22 which has aportion 114 rotatably supported in a bore 116 which is formed in thebushing 26.

The contact segments 60-65 are preferably made of brass, copper or othersheet metal which is highly conductive and which is easy to stamp andform, so that the various segments and the eyelet portion 110 may easilybe formed.

In accordance with one of the important features of the presentinvention, the insulating board 68 is formed with a plurality ofsemi-perforated segments or members 121-126 which project forwardly fromthe insulating board and are disposed in the spaces or openings betweenthe various contact segments. The semi-perforated members 121-126 servethe function of positively locating the contact segments 60-65 so as toprevent them from rotating about the rivets 81-85. In addition, thesemi-perforated members provide smooth surfaces which are flush with thefront surfaces of the contact segments 60-65, to provide for smoothcontact movement between the contact segments. The semi-perforatedmembers 121-126 are preferably punched forwardly from the insulatingboard 68 by a die-forming operation. The forward displacement of thesemi-perforated members is clearly shown in FIG. 8.

The semi-perforated segments or bosses 121-125 are arranged around thecircular path which is traversed by the outer contact points 48 and 49of the contactors 44. Thus, the outer contact points 48 and 49 ridealong the semi-perforated segments 121-125 when the contact points passbetween the various contact segments 61-65. It will be seen that thesemi-perforated segment 121 extends between the contact segments 61 and62. The semi-perforated segment 122 extends between the contact segments62 and 63. The semi-perforated segment 123 extends between the contactsegments 63 and 64. Similarly, the semiperforated segment 124 extendsbetween the contact segments 64 and 65 while the semi-perforated segment125 extends between the contact segments 65 and 61.

The remaining semi-perforated segment 126 is along the smaller circletraversed by the inner contact points 27 of the contactors 44. It willbe seen that the semiperforated segment 126 is disposed in a notch orcutout 128 formed in the central contact segment 60.

Each of the semi-perforated segments 121-126 has a smooth front surface130 which is substantially flush with the front surfaces of the contactsegments 60-65. A recess 132 in the rear side of the insulating board 68results from the formation of each of the semi-perforated segments121126.

In accordance with the present invention, it is preferred to employ amethod of manufacture in which all of the contact segments 60-65 areformed initially in a single piece or blank 134 which is stamped fromsheet metal. In addition to the various contact segments 60-65, theblank 134 incorporates an outer spider portion 136 which comprises acircular ring 138 extending around the outside of the blank. The spider136 also comprises a plurality of radial arms 141-149 which extendbetween the ring 138 and the various contact segments 61-65. It will beseen from FIG. 7 that each of the contact segments 61-65 is supported bytwo of the arms 141-149, except that the contact segment 64 is supportedonly by the arm 147, which is wider than most of the other arms.

The contact assembly is produced by mounting the one-piece blank 134 onthe front side of the insulating board 68. The semi-perforated segments121-126 result in the precise positioning and orientation of the blank134 relative to the insulating board. The blank 134 is secured to theboard 68 by inserting and setting the rivets 81-85. Finally, the spiderportion 136 of the blank 134 is removed by a trimming operation whichsevers all of the radial arms 141-149 along a circular trim line 150.

This method of manufacture is easy and extremely economical.Nevertheless, the various contact segments 60-65 are positioned with ahigh degree of precision. The semi-perforated segments 121-126 preventany movement of the contact segment 60-65 about the rivets 81-85.

In summary, the semi-perforated segments or bosses 121-126 play animportant role in the manufacture of the contact assembly, in that theone-piece metal blank 134 is precisely located and oriented by thesemi-perforated segments. After the rivets 81-85 have been set and thespider portion 136 of the blank 134 has been trimmed away along the line150, the semi-perforated segments 121-126 maintain the precisepositioning of the contact segments 60-65 and prevent any rotation ofthe segments about the rivets 81-85. Due to the provision of thesemiperforated segments, only one rivet is needed for each of the sheetmetal contact segments.

The semi-perforated segments 121-126 also form slide surfaces 130 whichare flush with the front surfaces of the contact segments 60-65 so as toprovide for smooth contact movement between the contact segments. Thesemi-perforated segments 121-126 virtually eliminate any roughness orany false detenting action in the operation of the switch.

The semi-perforated segments 121-125 are disposed between the contactsegments 61-65 and are effective to minimize the electrical arcingbetween the contactors 44 and the contact segments. The semi-perforatedsegments tend to cool and extinguish the arcs which form when thevarious circuits are broken by the movement of the contactors. Themelamine plastic coating on the semiperforated segments is especiallyresistant to the heat generated by the electrical arcs.

FIGS. 9-11 show the manner in which the present invention may be appliedto a quite diflerent contact construction 160, comprising anarcuately-shaped insulating board 162 which supports a one-piece contactplate 164. It will be seen that the contact plate 164 comprises threecontact segments 166, 167 and 168, all of which are connected togetherelectrically by continuous inner and outer border portions 170 and 172on the plate 164. Segmental openings 174 and 175 are formed in the plate164 to define the spaces between the segments 166468.

In accordance with the present invention, semi-perforated segments 178and 179 are punched forwardly from the insulating board 162, forreception in the openings 174 and 175. The semi-perforated segments 178and 179 corresponding in size and shape to the openings 174 and 175 andserve to locate the contact plate 174 with a high degree of precision onthe insulating board 162. The semiperforated segments 178 and 179 arepreferably punched forwardly from the insulating board 162 by adie-forming operation. It will be seen that the front surfaces of thesemi-perforated segments 178 and 179 are flush with the front surfacesof the contact segments 166-168, so as to provide for smooth contactmovement between the contact segments.

Suitable means are provided to secure the contact plate 164 to theinsulating board 162. As shown, this is accomplished by two pairs ofinner and outer tabs 181 and 182 which project rearwardly from the metalplate 164 and are bent over behind the insulating board 162. The innertabs 181 project through slots or openings 183 in the insulating board162. Notches 184 are formed in the board 162 to receive the outer tabs182.

An inclined semi-perforated segment 186 is formed from the insulatingboard 162 adjacent the contact segment 166 to provide a ramp, wherebycontacts may be moved in a smooth manner onto and otf the contactsegment 166. The semi-perforated segment 186 slants from a level flushwith the contact segment 166 to the level of the front surface of theboard 162, as shown to best advantage in FIG. 11.

Thus, the present invention is applicable to a wide variety of contactconstructions, in which it is desired to achieve precise and positivelocation of sheet metal contact members on an insulating plate or board.The present invention has the added advantage of providing smoothcontact movement between the contact segments.

Various other modifications, alternative constructions and equivalentsmay be employed without departing from the true spirit and scope of theinvention, as exemplified in the foregoing description and defined inthe following claims.

I claim:

1. A contact construction for switches, comprising a supporting board ofinsulating material, a plurality of conductive segmental contact platesmounted against one side of said board, each of said plates having asingle rivet extending through aligned openings in said plate and saidboard and securing said plate to said board, a plurality ofsemi-perforated laterally offset segments formed in said supportingboard and projecting therefrom between said plates for positivelylocating said plates on said board and preventing rotation of saidplates about said rivets, said semi-perforated segments projecting fromsaid board and being substantially flush with said plates and therebyforming slide surfaces for smooth contact movement between said plates.

2. A contact construction for switches or the like, com prising aninsulating board, a plurality of contact plates mounted against thefront surface of said board, a plurality of fasteners extending throughopenings in said plates and said board and securing said plates to saidboard, only one of said fasteners extending through each plate, and aplurality of forwardly punched members formed in said board andprojecting forwardly so as to be flush with said plates, said forwardlypunched members being disposed between said plates and being effectiveto positively locate said plates on said board, said forwardly punchedmembers forming slide surfaces for smooth contact movement between saidplates.

3. In a contact construction for switches or the like, the combinationcomprising an insulating board, a contact plate mounted on said board,and a slanting semiperforated laterally displaced member formed in saidboard adjacent said plate and slanting from a level flush with saidplate to a level flush with said board.

References Cited UNITED STATES PATENTS 1,410,914 2/1922 Hartzell29155.54 2,026,773 1/1936 Dressel et al. 200"11 2,925,647 2/ 1960 Joneset al 200155.55 2,949,511 8/1960 Glueckstein et al. 20011 3,038,1386/1962 Peterson 29155.54 X 3,075,281 1/1963 Spooner 29-15555 3,118,0371/1964 Scott 200166 3,140,364 7/1964 Swanke et al. ZOO-11 3,147,3599/1964 Hanna 200-166 3,159,722 12/1964 Cobb et al. 2001l ROBERT K.SCHAEFER, Primary Examiner.

KATHLEEN H. CLAFFY, Examiner.

H. O. JONES, Assistant Examiner.

1. A CONTACT CONSTRUCTION FOR SWITCHES, COMPRISING A SUPPORTING BOARD OFINSULATING MATERIAL, A PLURALITY OF CONDUCTIVE SEGMENTAL CONTACT PLATESMOUNTED AGAINST ONE SIDE OF SAID BOARD, EACH OF SAID PLATES HAVING ASINGLE RIVET EXTENDING THROUGH ALIGNED OPENINGS IN SAID PLATE AND SAIDBOARD AND SECURING SAID PLATE TO SAID BOARD, A PLURALITY OFSEMI-PERFORATED LATERALLY OFFSET SEGMENTS FORMED IN SAID SUPPORTINGBOARD AND PROJECTING THEREFROM BETWEEN SAID PLATES FOR POSITIVELYLOCATING SAID PLATES ON SAID BOARD AND PREVENTING ROTATION OF SAIDPLATES ABOUT SAID RIVETS, SAID SEMI-PERFORATED SEGMENTS PROJECTING FROMSAID BOARD AND BEING SUBSTANTIALLY FLUSH WITH SAID PLATES AND THEREBYFORMING SLIDE SURFACES FOR SMOOTH CONTACT MOVEMENT BETWEEN SAID PLATES.